Can't go back to Windows 8.1 with Bing, using 8.1 Media Creation tool

Computer Type: PC/Desktop
System Manufacturer/Model Number: Fujitsu Siemens Scaleo P AMI BIOS 1005.1001 03/02/2005
OS: Windows 10 x86 14383 Insider Pro and Core 10240
CPU: Intel socket 775 Pentium 4 540 HT 3200 Prescott
Motherboard: Fujitsu Siemens ASUS P5GD1-FM/S AMI BIOS 1005.1001
Memory: 2GB DDR
Graphics Card: GeForce 9500GT 512MB driver version 341.92
Sound Card: on-board Realtek High Definition Audio
Monitor(s) Displays: Hewlett Packard HP vs17
Screen Resolution: 1280 x 1024
Keyboard: Logitech K120
Mouse: Logitech
PSU: Antec 380W
Case: Antec NSK 4000B
Cooling: Big case fans
Hard Drives: 2 Seagate 500 GBs, Maxtor 300GB, WD160 all rescued from old Sky and NTL STB throwouts.
Internet Speed: BT 70 down 20 up
Browser: Edge
Antivirus: MS Defender
Other Info: This is seriously old kit - dating back to early 2005. Almost all of it was thrown out as trash at some time! The keyboard and mouse, and the Graphics Card cost about £20 altogether. It lives in a case with 8 drive bays, and runs several multibooting systems - from Windows XP to 10, and some Linux distributions without problems, and generally with good speed.

Computer Type: Laptop
System Manufacturer/Model Number: Acer Travelmate 2423
OS: Windows 10 14393.2007 1607 x86
CPU: Celeron M 1.50GHz 1 core 32-bit
Motherboard: Acer Phoenix BIOS 23 May 2006
Memory: 2 GB, 1.45 GB available
Graphics Card: Mobile Intel® 915GM/GMS, 910GML Express Chipset Family
Sound Card: Realtek AC'97
Monitor(s) Displays: Advent (Mirage driver) dfmirage.sys 2.0.105.0
Screen Resolution: 1400x900
Keyboard: Logitech K120
Mouse: Logitech M-U0026
PSU: Acer, External
Case: Clamshell
Cooling: Ext. laptop fan assist
Hard Drives: Kingspec PATA IDE SSD 128GB
Internet Speed: 80 down 18 up (BT)
Browser: Chrome Canary
Antivirus: Defender
Other Info: Originally XP home x86 U/G to Pro, U/G Windows7 Pro, U/G Windows 10 Pro screen hinges show fatigue cracks on the clamshell screen damaged when dropped hence ext monitor; battery dead, touchpad barely usable, and keyboard pretty knackered, hence ext kb and mouse. internal WiFi adapter failed, so use wired ethernet. int DVD also now unusable, modem disabled